ES2197907T3 - METHOD FOR STERILIZING PRODUCTS. - Google Patents

Abstract

Methods are disclosed for sterilizing biological products to reduce the level of active biological contaminants such as viruses, bacteria, yeasts, molds, mycoplasmas and parasites.

Description

Method to sterilize products.

Field of the Invention

The present invention relates to a method for sterilize products to remove biological contaminants such like viruses, bacteria, yeasts, molds, mycoplasmas and parasites

Background of the invention

Several products that are prepared for human use, veterinary or experimental may contain unwanted contaminants and potentially dangerous such as viruses, bacteria, yeasts, molds, mycoplasmas and parasites. Therefore, it is sum importance to determine if such products lack Contaminants before use. This is especially important when  the product is going to be administered directly to a patient, by example, in blood transfusions, organ transplants and Other forms of human therapies. This is also important for various biotechnological products that are grown in media that they contain various types of plasma and that may be prone to Mycoplasmas or other viral contaminants.

Previously, most procedures have involved methods that select or test products with respect to a particular contaminant instead of removing the contaminant of the product (1). Products that give a positive result in a Test for a contaminant simply is not used. The examples of Selection procedures include testing a virus particular in human blood from blood donors. Without However, such procedures are not always reliable and cannot detect the presence of viruses in very low numbers. In view of the  consequences associated with a false negative result, this reduce the value or reliability of the test. In certain cases, for example, in the case of acquired immunodeficiency syndrome (AIDS), false negative results can be threatening for life. In addition, in some cases, it may take weeks, and Even months, determine if the product is contaminated or not.

Certain more recent efforts have focused in methods to remove or inactivate contaminants present in the products. Such methods include heat treatment, filtration, addition of chemical inactivators and gamma irradiation (2). It's okay documented that gamma irradiation is effective in destroying viruses and bacteria (2, 3). In fact, one author concludes that the gamma irradiation is the most effective method in reducing or elimination of virus levels (2). However, when Applies to radiation sensitive products, such as blood or blood products, gamma irradiation may also have harmful effects on the product itself. In particular, it has  demonstrated that high radiation doses are harmful to red blood cells, platelets and granulocytes (3).

Summary of the invention

In view of the above, it is necessary to provide a method to sterilize products that is effective in elimination of biological contaminants and at the same time not have adverse effects on the product. The examples of Contaminants include viruses, bacteria, yeasts, molds, Mycoplasmas and parasites.

Accordingly, the present invention provides a method to sterilize a product comprising irradiate the product with gamma radiation at a rate of about 0.5 kGy / h at about 3.0 kGy / h during a period of time less than 10 hours.

By the method of the present invention, the gamma radiation is supplied for a period of time prolonged that substantially reduces damage to the product. Typically, irradiation is performed over a period of time. not less than 10 hours, preferably about 20 to about 40 hours, more preferably about 20 at about 30 hours. The irradiation rate varies from approximately 0.5 kGy / h to approximately 3.0 kGy / hr, depending of the product to be sterilized as well as the duration of the irradiation. The total amount of irradiation provided typically it is in the range of about 20 to approximately 32 kGy, since it has been shown that these levels they are effective in destroying contaminants such as virus.

The product is irradiated in a form that contains preferably less than 20% solids. Therefore certain Products must be diluted before irradiation. The tratment of Diluted products also serve to reduce the Product degradation during irradiation. The choice of Diluent depends on the nature of the product to be irradiated. By For example, when red blood cells are irradiated, a physiologically acceptable diluent such as phosphate citrate dextrose.

The process according to the present invention It can be done at room temperature and does not require refrigeration, freezing or chemical treatment of the product before that the process is carried out. This avoids some of the stages. of extra treatment that are present in certain processes of the prior art

The method of the present invention is useful in the Treatment of organic products that are sensitive to irradiation. Such products may be prone to degradation. when irradiated by conventional methods. However, it is not expect irradiation of products sensitive to irradiation by the present method is detrimental to products. The method typically applies to biological products. such as blood and blood components, although it is not limited to the same.

In cases where cells are going to radiate live (such as blood cells), a remover can be added that joins free radials and other materials that are Toxic to cells. A suitable eliminator is ethanol.

The effectiveness of the method of the present invention It is contrary to what other specialists have foreseen in this area. In particular, in U.S. Patent No. 4,620,908 (1) indicates that if gamma irradiation was applied on a protein material at room temperature, the material is it would destroy almost completely or be destroyed to such an extent that the material would become virtually ineffective. In contrast to this, when tested in blood, the method of the present invention has not destroyed the viability of the cells contained in the same.

EP 0 334679 A1 shows the irradiation of blood plasma products or plasma derivatives at temperatures from -20ºC to -60ºC using dosages of 1 or 2 to 20 or 40 KGy / hour, conventionally from 4 to 15 kGy / hour.

Description of preferred embodiments

The following examples are provided for illustrate the method of the present invention and should not be considered limiting the scope of the invention.

Example 1 Blood Sterilization

A 200 ml bag of red blood cells was used One day packaged. Ethanol was added to the cells to get a final ethanol concentration of 0.01%. Red blood cells are diluted by a factor of one in ten using a solution of Modified Citrate Phosphate Dextrose (CPD) that had a pH of about 6.4 to 6.7 and it had the following composition in a 500 ml total volume:

       \ catcode` \ # = 12 \ nobreak \ centering \ begin {tabular} {| ll |} \ hline
Citric Acid Monohydrate \ + 0.2 g \\ Sodium Citrate Dihydrate \ +
26.3 g \\ Monobasic Sodium Phosphate \ + 2.2 g \\ Sodium Phosphate
Dibasic \ + 1.0 g \\ Dextrose \ + 3.2 g
\\\ hline \ end {tabular} \ par \ vskip.5 \ baselineskip
    

The cells were irradiated in a gamma irradiator commercial size containing a cobalt 60 source grid. Irradiation was performed without support in an unprotected box. The cells were irradiated for twenty four hours at a rate of approximately 1 kGy / h. After the irradiation period, the red blood cells were examined visually and found to be viable, with a bright red color. A control sample, composed of packed red blood cells that were not diluted with the CPD solution described above, were not viable after irradiation

Four days after the procedure irradiation, the diluted cells were tested for levels of various blood components and the results are shown in table 1. The control sample consisted of blood from the same bag as the test sample, but did not experience irradiation. Table 1 demonstrates that dilution and irradiation of human red blood cells did not significantly alter the count of white blood cells. Values of platelet count and hematocrit were slightly lower than in the control, without However, these values remain within the range. observed in the blood of a normal adult. Hemoglobin level was higher than the control, indicating that some blood cells Reds were lysed during the procedure. This is also demonstrated.  by the lower red blood cell count. However, to unlike what has been previously published, a radiation of up to 25 kGy did not destroy the blood components by the present procedure The cells were also counted and discovered that they were viable after 25 kGy of irradiation gamma

TABLE 1

       \ catcode` \ # = 12 \ nobreak \ centering \ begin {tabular} {| l | l | l |} \ hline
Component \ + Irradiated Blood \ + Control Blood \\\ hline
White Blood Cells \ + 4 K / mm3 \ + 4.8 K / mm3 \\\ hline
Red Blood Cells \ + 3 Mi / mm3 \ + 7.2 Mi / mm3 \\\ hline
Hemoglobin \ + 42 g / dl \ + 21 g / dl \\\ hline Hematocrit \ + 46%
\ + 64% \\\ hline Platelet \ + 100 k / mm 3 \ + 120 k / mm 3
\\\ hline \ end {tabular} \ par \ vskip.5 \ baselineskip
    

Example 2 Dextrose Sterilization

Solutions containing dextrose (or glucose) in the treatment of carbohydrate reduction and fluids, in the treatment of hypoglycemia, as an element for expand plasma, on renal dialysis and to neutralize hepatotoxins (4,5). Dextrose is also the preferred source of Carbohydrates in parental nutrition regimens (4,5). In all  previous applications, dextrose must be sterilized before use. Sterilization of products containing dextrose is generally performed by thermal sterilization or sterilization in autoclave. Unfortunately, it has been reported that these methods degrade or caramelize solutions containing dextrose causing a color change in the solution (5). It has also been reported that gamma glucose irradiation breaks down solutions that contain glucose (6). Therefore, you need a method that can sterilize products containing dextrose that do not degrade the own product. In view of the problems of the prior art, a dextrose solution was treated according to the method of present invention as indicated below.

A 5% dextrose solution was irradiated during 24 hours, at a speed of approximately 1 kGy / h. After the irradiation, the product was tested and it was discovered that there was no no change in the visible light spectrum compared to the non irradiated control. Therefore, the present method can be useful in sterilizing products containing dextrose.

After the previous experiment, they were irradiated new solutions of dextrose at 5 and 50% at 25 kGy for 36 hours at room temperature. The results were similar to those described above. In addition, UV / VIS scans were obtained and demonstrated a complete absence of the peak at 283.4 nm for `` furfurales '' according to the U.S.P. On the contrary, the samples of dextrose sterilized using an autoclave contain the peak of furfural at 283.4.

Example 3 Sterilization of Human Serum Albumin

Normal human serum albumin was irradiated as a 25% salt solution at a total dose of 25 kGy for 36 hours using a Gamma 220 cell. During irradiation it is not controlled the temperature, but it is estimated that the vessel that It contained the albumin solution was at approximately 23 ° C. In Table 2 shows the results of the HPLC analysis.

TABLE 2

       \ catcode` \ # = 12 \ nobreak \ centering \ begin {tabular} {| c | c | c |} \ hline
Parameter \ + Control (%) \ + Irradiated (%) \\\ hline Polymer \ + 2
\ + 3 \\\ hline Dimer \ + 7 \ + 8 \\\ hline Monomer \ + 90 \ + 86
\\\ hline Low Molecular Weight \ + 1 \ + 3 \\\ hline pH \ + 7.05 \ +
6.97 \\\ hline NTU (must be> 20) \ + 11.4 \ + 11.4
\\\ hline \ end {tabular} \ par \ vskip.5 \ baselineskip
    

As the results show, the albumin of Normal human serum can be irradiated safely at 25 kGy at ambient temperature without adversely affecting the essential properties of the protein. This has not been proven. previously. All other attempts to radiate albumin from Whey require it to radiate in the frozen state. This increases the cost and difficulty of performing irradiation.

Example 4

Normal human blood was taken from a donor healthy in a heparinized tube; washed three times with solution of Conventional CPD, and then diluted to 1:20 with CPD containing 0.01% v / v ethanol. This last CPD solution with 0.01% v / v ethanol is called SCPD. Then, they put aliquots of 2 ml in 10 ml plastic test tubes and irradiated to different doses up to 26 kGy for 36 hours at temperature environment. There was no hemolysis and the cells seemed intact although somewhat large and slightly irregular. Table 3 shows present the results of three different experiments.

TABLE 3

       \ catcode` \ # = 12 \ nobreak \ centering \ begin {tabular} {| c | c | c | c | c | c | c | c | c |} \ hline
 Parameter \ + RBC1 \ + HGB2 \ + HCT3 \ + MCV4
\ + MCH ^ {\} MCHC ^ {6} \ + RDW ^ {7} \ + Indicators \\\ hline
1 * \ + 1.08 \ + 41 \ + 0.097 \ + 89.5 \ + 38.3 \ + 427 \ + 17.7 \ +
Almost Normal \\ Control \ + 0.99 \ + 33 \ + 0.089 \ + 90.2 \ + 33.0
\ + 366 \ + 15.3 \ + \\\ dddcline {2} {9} 2 * \ + \ + \ + \ + 95.0 \ +
32.3 \ + 339 \ + 12.0 \ + \\ \ + \ + \ + \ + \ + \ + \ + \ + \\\ hline 12
kGy 1 \ + 1.22 \ + 45 \ + 0.166 \ + 135.8 \ + 36.5 \ + 269 \ + 27.3
\ + 1 + Anisocytosis \\ \ + 1.38 \ + 45 \ + 0.199 \ + 144.7 \ + 33.0
\ + 228 \ + 24.9 \ + 3 + Macrocytosis \\\ hline 1 \ + 1.04 \ + 32 \ +
0.169 \ + 163.0 \ + 31.3 \ + 192 \ + 18.8 \ + 1 + Anisocytosis \\
16kGy \ + 0.54 \ + 29 \ + 0.088 \ + 162.5 \ + 54.5 \ + 335 \ + 18.8
\ + 3 + Macrocitocis \\\ dddcline {2} {9} 2 \ + 0.82 \ + 27 \ + 0.128 \ +
156.5 \ + 32.8 \ + 209 \ + 19.8 \ + 2 + Anisocytosis \\ \ + 0.81 \ +
26 \ + 0.124 \ + 152.6 \ + 32.4 \ + 212 \ + 20.2 \ + 3 + Macrocitocis
\\\ hline 1 \ + 0.79 \ + 244 \ + 0.125 \ + 158.4 \ + 30.8 \ + 194
\ + 19.4 \ + 1 + Anisocytosis \\ 20 kGy \ + 1.26 \ + 28 \ + 0.203 \ +
161.5 \ + 22.1 \ + 137 \ + 19.0 \ + 3 + Macrocitocis \\\ dddcline {2} {9}
 2 \ + 0.93 \ + 30 \ + 0.141 \ + 151.5 \ + 32.3 \ + 213 \ + 20.1 \ +
2 + Anisocytosis \\ \ + 0.92 \ + 30 \ + 0.143 \ + 155.5 \ + 32.1 \ +
207 \ + 20.5 \ + 3 + Macrocitocis \\\ hline 26 kGy 1 \ + 1.15 \ + 34
\ + 0,180 \ + 155,9 \ + 29,4 \ + 189 \ + 19,3 \ + 1 + Anisocytosis \\
\ + 1.15 \ + 34 \ + 0.176 \ + 153.0 \ + 29.9 \ + 195 \ + 23.4 \ +
3 + Macrocitocis \\\ hline \ multicolumn {9} {r} {* Experiment 1 and
Experiment
2.} \\\ end {tabular} \ par \ vskip.5 \ baselineskip
    

1. Red Blood Cell Count: Cells x 10 12 / liters.

2. Hemoglobin: grams / liter.

3. Hematocrit.

4. Average corpuscular volume: Femtoliters.

5. Average corpuscular hemoglobin: picograms.

6. Corpuscular hemoglobin concentration average: grams / liter.

There was no hemolysis and the cells seemed intact although somewhat large and slightly irregular. The cells they were easily suspended and reconstituted in buffer new.

The following three experiments (examples 5, 6 and 7) were performed to determine the effectiveness of the method when Treats blood that contains HIV. In each example, the cells are They treated similarly. The analysis was performed in a second independent laboratory The second laboratory was also chosen because I could manipulate the AIDS virus. In these experiments, the  Cells were shaken gently after 12, 16 and 24 hours. In addition, in the third experiment, (example 7), the cells are put in T25 flasks to provide a surface area higher and reduce the concentration due to sedimentation in the bottom of centrifuge tubes.

Example 5 Blood sterilization containing HIV

The following experiment was performed with the following specific objectives:

one.

Evaluate the toxicity of the process towards red blood cells (RBC).

two.

Evaluate the anti-retroviral activity of the process.

Process

Initially, 2 ml of blood were obtained anticoagulated from a donor HIV-seronegative The blood was centrifuged and separated the plasma. The remaining cell pellet was resuspended in 10 ml of the CPD buffer and centrifuged. This washing process is repeated a total of three times. The final sediment was resuspended in 40 ml of the SCPD buffer, and distributed in plastic tubes in 2 ml aliquots, retaining 16 separate aliquots for a additional handling 8 of these tubes were added a aliquot of HTLV-IIIB. This is a strain of HIV virus laboratory, and each of the tubes to be infected is 100 infectious doses of tissue culture (TCID) were added. For the remaining 8 tubes, a `` simulated '' infection was performed adding a small amount of a laboratory buffer not Infectious, phosphate buffered saline (PBS). I know four infected and four non-infected tubes were submitted to the process infected. For comparison, the remaining 8 tubes (four infected and four uninfected) were handled in a way identical, with the exception that they did not undergo the process.

It should be noted that at the beginning of study, a separate aliquot of donor blood was obtained. This was processed in the clinical hematology laboratory and was performed a complete blood count. These baseline results are compared with the repeated trial in the study rates, which it included the evaluation of four processed samples and four unprocessed samples, without any of them being HIV infected.

An 0.5 ml aliquot was inoculated from each of infected study samples in mononuclear cells (MC) which had been obtained 3 days before. These cells had suspended in RPMI culture medium, with 10% calf serum fetal and other additives (penicillin, streptomycin, glutamine, HEPES buffer) together with 1 µg / ml PHA-P. To the same time as this inoculation, the cells were resuspended in new medium with rIL-2 (20 U / ml). The crops are They kept for 7 days. Twice a week, one was collected portion of the culture medium to measure p24 antigen levels HIV (ELISA commercial kit, Coulter Electronics, Hialeah, FL) for Measurement of viral growth.

A separate aliquot of the eight samples was used infected study for titration experiments viral.

In summary, several dilutions were inoculated into four-fold series of fluids containing viruses (which ranged from 1:16 to 1: 65,536) in triplicate on culture plates of 96-well flat bottom tissues. Stimulated MCs were added with PHA to each well (4 million cells in 2 ml of medium culture, with IL-2). An aliquot of the supernatant from each of the culture wells twice per week to measure HIV p24 antigen levels. A well is evaluated as `` positive '' if the value of the HIV p24 antigen was > 30 pg / ml. Viral titration was calculated according to the Spearman-Karber method (see manual of ACTG virology protocol) using the following equation:

M = xk + d [0.5- (1 / n) r]

M: degree (in log 4)

xk: highest dilution dose

d: space between dilutions

n: number of wells per dilution

r: sum of the total number of wells

Results

Table 4 shows the parameters of red blood cells for the basal sample as well as for the samples of Study not processed and processed.

TABLE 4

       \ catcode` \ # = 12 \ nobreak \ centering \ begin {tabular} {| c | c | c | c |} \ hline
 Sample / Number \ + MCV \ + MCH \ + MCHC \\\ hline Basal \ + 94.5
\ + 32.0 \ + 339 \\\ hline Not processed-1 \ + 91.4
\ + 34.4 \ + 376 \\\ hline Not processed-2 \ + 90.2
\ + 37.9 \ + 420 \\\ hline Not processed-3 \ + 92.1
\ + 40.0 \ + 433 \\\ hline Not processed-4 \ + 91.0
\ + 40.2 \ + 442 \\\ hline Processed-1 \ + 133.4 \ +
37.8 \ + 284 \\\ hline Processed-2 \ + 131.5 \ +
45.0 \ + 342 \\\ hline Processed-3 \ + 128.5 \ +
38.9 \ + 303 \\\ hline Processed-4 \ + 131.1 \ +
39.4 \ + 301
\\\ hline \ end {tabular} \ par \ vskip.5 \ baselineskip
    

The abbreviations used in Table 4 are explained. in table 3.

As described above, it established HIV cultures using 0.5 ml aliquots of unprocessed and processed study samples. Table 5 shows show p24 antigen levels (pg / ml) of the study samples of day 4 and day 7 of cultivation.

TABLE 5

       \ catcode` \ # = 12 \ nobreak \ centering \ begin {tabular} {| c | c | c |} \ hline
Sample / Number \ + p24-DAY 4 \ +
p24-DAY 7 \\\ hline Not processed-1
\ + 1360 \ + 464 \\\ hline Not processed-2 \ + 1180
\ + 418 \\\ hline Not processed-3 \ + 1230 \ + 516
\\\ hline Not processed-4 \ + 1080 \ + 563 \\\ hline
Processed-1 \ + 579 \ + 241 \\\ hline
Processed-2 \ + 760 \ + 303 \\\ hline
Processed-3 \ + 590 \ + 276 \\\ hline
Processed-4 \ + 622 \ + 203
\\\ hline \ end {tabular} \ par \ vskip.5 \ baselineskip
    

Finally, a sample was selected not processed and a processed sample for the realization of the Direct viral titration without culture. The results are shown in table 6.

TABLE 6

       \ catcode` \ # = 12 \ nobreak \ centering \ begin {tabular} {| c | c |} \ hline
Sample / Number \ + Titration (log 10 ml) \\\ hline No
processed-1 \ + 1,5 \\\ hline
Processed-1 \ + 0,0
\\\ hline \ end {tabular} \ par \ vskip.5 \ baselineskip
    

Red blood cells were affected minimally by the process, although some macrocytosis was observed reproducible. Although after co-culture of samples processed there seemed to be some residual live viruses, this does not It was confirmed by direct titration experiments.

Example 6

The objective of this experiment was to evaluate the process toxicity to red blood cells in a way exhaustive

Methods

For this experiment, 1 ml of blood was obtained anticoagulated from the same donor HIV-seronegative than in the first experiment. The Blood was centrifuged and the plasma was removed. Cell sediment The remaining was resuspended in 10 ml of CPD buffer and centrifuged. East  washing process was repeated a total of three times. Sediment final was resuspended in 20 ml of the SCPD buffer, and distributed in plastic tubes in 2 ml aliquots, retaining 10 aliquots for additional handling Eight tubes were subjected to the process, while the two end tubes were retained as tubes of unprocessed control. After processing, the ten tubes are centrifuged and the resulting sediment was resuspended in 100 buffer buffer A complete blood count was performed on these re-concentrated study samples.

As in the first experiment, a aliquot separated from donor blood when the sample was taken study. A complete blood count was performed on this sample. basal. How the study samples were reconcentrated to a 33-50% of its original state, could be performed more direct comparisons with the baseline sample than were possible in our previous experiment.

Results

Table 7 shows blood cell parameters reds for the baseline sample as well as for the study samples not processed and processed. The abbreviations used in table 7 They are defined in table 3.

TABLE 7

       \ catcode` \ # = 12 \ nobreak \ centering \ begin {tabular} {| c | c | c | c | c | c |} \ hline
 Sample / Number \ + RBC \ + HGB \ + MCV \ + MCH \ + MCHC \\\ hline
Baseline \ + 4.76 \ + 152 \ + 94.9 \ + 31.9 \ + 336 \\\ hline No
processed-1 \ + 0.99 \ + 33 \ + 90.2 \ + 33.0 \ +
366 \\\ hline Not processed-2 \ + 1,08 \ + 41 \ +
89.5 \ + 38.3 \ + 427 \\\ hline Processed-1 \ + 1.15
 \ + 34 \ + 153.0 \ + 29.9 \ + 195 \\\ hline
Processed-2 \ + 1.15 \ + 34 \ + 155.9 \ + 29.4 \ +
189 \\\ hline Processed-3 \ + 1.26 \ + 28 \ + 161.5
\ + 22.1 \ + 137 \\\ hline Processed-4 \ + 0.79 \ +
24 \ + 158.4 \ + 30.8 \ + 194 \\\ hline Processed-5
\ + 0.54 \ + 29 \ + 162.5 \ + 54.5 \ + 335 \\\ hline
Processed-6 \ + 1.04 \ + 32 \ + 163.0 \ + 31.3 \ +
192 \\\ hline Processed-7 \ + 1.35 \ + 45 \ + 144.7
\ + 33.0 \ + 228 \\\ hline Processed-8 \ + 1.22 \ +
45 \ + 135.8 \ + 36.5 \ + 269
\\\ hline \ end {tabular} \ par \ vskip.5 \ baselineskip
    

There were macrocytosis of the cells that were present in all processed samples. Levels were measured comparable hemoglobin in unprocessed samples and processed. Absolute values were appropriate for dilution residual. Red blood cells are preserved.

Example 7

The objective of this example was to verify and expand the results obtained in example 6.

Methods

For this experiment, 5 ml of anticoagulated blood from the same donor HIV-seronegative than in the first two experiments The blood was centrifuged and the plasma was removed. The remaining cell pellet was resuspended in 100 ml of CPD buffer and It was centrifuged. This washing process was repeated a total of three times. The final sediment was resuspended in 100 ml of the SCPD buffer and distributed in 25 ml aliquots, in culture flasks of T25 fabrics, retaining the four aliquots for handling  additional. Two flasks underwent the process, while the two others were retained as unprocessed control flasks. After processing, the content of each of the the flasks and a visual determination of the capacity was made of cells absorb oxygen (adopting a red color bright after exposure to ambient air). After this, the flask contents were aspirated and centrifuged, resuspended residual sediment in a small volume of buffer. A Complete blood count in these reconcentrated study samples.

As in examples 5 and 6, a aliquot separated from blood from the donor when it was obtained The study sample. A complete blood count was performed on this basal sample. How the study samples were reconcentrated to a 33-50% of its original state, could be performed direct comparisons of several specific parameters with the basal sample.

Results

After the visual inspection, they could not appreciate differences between processed study samples and not processed. Specifically, there seemed to be a distribution Uniform well-suspended cells. After exposure to air Atmosphere, the content of all flasks adopted a somewhat red color brighter. No specific quantitative measurements were made of oxygenation.

Table 8 shows blood cell parameters reds for the baseline sample as well as for the study samples not processed and processed. The abbreviations used in table 8 They are defined in table 3.

TABLE 8

       \ catcode` \ # = 12 \ nobreak \ centering \ begin {tabular} {| c | c | c | c | c | c |} \ hline
 Sample / Number \ + RBC \ + HGB \ + MCV \ + MCH \ + MCHC \\\ hline
Baseline \ + 4.75 \ + 153 \ + 95.0 \ + 32.3 \ + 339 \\\ hline No
processed-1 \ + 0.93 \ + 30 \ + 151.5 \ + 32.3 \ +
213 \\\ hline Not processed-2 \ + 0.92 \ + 30 \ +
155.5 \ + 32.1 \ + 207 \\\ hline Processed-1 \ +
0.82 \ + 27 \ + 156.5 \ + 32.8 \ + 209 \\\ hline
Processed-2 \ + 0.81 \ + 26 \ + 152.6 \ + 32.4 \ +
212
\\\ hline \ end {tabular} \ par \ vskip.5 \ baselineskip
    

This experiment was designed to approximate with more accuracy to the conditions of the red blood cells that are going to transfuse a patient and, consequently, was performed to higher volumes On a preliminary basis, it doesn't seem that the process negatively affect the ability of red blood cells to transport oxygen, although this must be measured more formally. From interesting way, in this experiment, there was no difference in cell size between processed and unprocessed samples, both can be compared to a large extent with the baseline value. This It would be repeated. In all study samples levels were measured of comparable hemoglobin.

Although the examples refer to embodiments specific to the method of the present invention, it should be appreciated that the method can be used to treat a diversity Extremely broad products that require sterilization. The fact that the method has proven efficacy in the blood, which is a fragile biological material, makes it reasonable predict that the method can be used on many products equally sensitive. Examples of other products that may treated include pharmaceutical compounds, proteins, acids nucleic, blood components, body fluids (such as the cerebrospinal fluid or saliva), liposomes, products that contain glucose, cell cultures, fetal bovine serum, marrow bone, organs, food and cosmetics such as shampoos, lotions and creams

References

1. Van Duzer , John P .; Method for Destroying Microbial Contamination in Protein Materials; U.S. Patent No. 4,620,908; November 4, 1986 .

2. Keathly , JD Et. to the.; Is There Life after Irradiation? Part 2; BioPharm July-August 1993 .

3. Leitman , Susan, F; Use of Blood Cell Irradiation in the Prevention of Post Transfusion Graft-vs-Host Disease; Transfusion Science 10: 219-239, 1989 .

4. The Merck Index, Eleventh Edition: Merck & Co. Inc. 1989 .

5. Martindale Extra Pharmacopecia p. 1,265.

6. Kawakishi et al; Radiation-Induced Degradation of D-glucose in Anaerobic Condition. Agric Biol. Chem . June 1977

Claims (18)

1. A method to sterilize a product that comprises irradiating the product with gamma radiation at a rate from 0.5 kGy / h to 3.0 kGy / h for a period of time not less than 10 hours. 2. A method according to claim 1, where said product to be sterilized is irradiated in a way that It has a solids content of not less than 20% by weight. 3. A method according to claim 1, where the total amount of irradiation provided is in the range from about 20 to about 32 kGy. 4. A method according to claim 1, where said product radiates over a period of 20 at 40 hours 5. A method according to claim 1, where said product radiates over a period of 20 30 hours 6. A method according to claim 1, where said product is an organic product. 7. A method according to claim 1, where said product is a biological product. 8. A method according to claim 1, where said product is blood or a component thereof. 9. A method according to claim 4, where said product is diluted with a phosphate citrate solution dextrose. 10. A method according to claim 1, where said product contains dextrose. 11. A method according to claim 1, where said product is a protein. 12. A method according to claim 11, where said product is an antibody. 13. A method according to any one of claims 1 to 12, wherein said product is irradiated in presence of a eliminator. 14. A method according to claim 13, where said eliminator is a eliminator for three radicals. 15. A method according to claim 13, where said eliminator is ethanol. 16. A method according to claim 15, where said ethanol is in a final concentration of 0.01% and said blood or blood product is diluted before irradiation in a physiologically acceptable diluent to achieve a final dilution of at least 1:10. 17. A method according to claim 16, wherein said acceptable physiological diluent is a solution of modified citrate phosphate dextrose having a pH in the range from about 6.4 to about 6.7. 18. A method according to claim 17, wherein said phosphate dextrose citrate solution contains approximately 0.01% v / v ethanol.